1. Field of the Invention
The present invention relates to a method of manufacturing a nitride semiconductor device used, e.g., for amplifying high frequency signals, and also relates to a burn-in apparatus used in that method.
2. Background Art
Japanese Laid-Open Patent Publication No. S62-267676 discloses a technique in which a semiconductor device is burned-in using an evaluation apparatus. Alessandro Chini et al. disclose failure mechanisms of semiconductor devices which have been subjected to stress due to burn-in, etc. (see Alessandro Chini et al., “Analysis of GaN HEMT Failure Mechanisms During DC and Large-Signal RF Operation,” IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 59, NO. 5, May 2012, p. 1385).
A problem associated with nitride semiconductor devices has been that long-term use of a nitride semiconductor device results in a decrease in its output RF signal power and an increase in its gate current, making it impossible to provide a nitride semiconductor device having high reliability over long periods of operation.